Lock-controlled nut and set-screw guard.



PATENTED NOV. 12, 1907.

K. E. & J. AHLBERG. LOOK CONTROLLED NUT AND SET SCREW GUARD.

APPLICATION FILED FEB. 23, 1907.

UNITED STATES PATENT orrron.

KARL E. AHLBERG AND JOSEPH AHLBERG, OF CHICAGO, ILLINOIS.

LOCK-CONTROLLED NUT AND SET-SCREW GUARD.

Specification of Letters Patent.

Patented Nov. 12 1907.

Application filed February 23. 1907. Brisl No. 359.013.

To all whom it may concern: Be it known that we, KARL E. ArrLBERe and JOSEPH AHLBERG, citizens of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Lock-Controlled Nut and Set-Screw Guards, of which the following is a specification.

This invention relates to guards for the heads or nuts of bolts, the heads of set-screws, and similar devices, and the object of -the invention is to provide a simple, inexpensive, and eflicient device to serve as a guard for set-screws, bolts, and similar fastening devices whereby articles of more or less value are often secured or supported in places or positions where they are liable to be abstracted or stolen; For instance, automobile and bicycle lamps, whichfrequently represent considerable value, are commonly mounted on a vertical bracket and secured against accidental displacement by'an ordinary headed setscrew tapped through the sleeve on the shank of the lantern which engages the postof the bracket. Where the lantern is thus mounted, it isan easy matter for a person so inclined to loosen the set-screw and remove 'and make off with the lantern. Many other articles of more or less value are similarly mounted and secured, making their unlawful abstraction an easy matter on the part of dishonest persons.

Our present invention affords a lock-controlled guard or shield for the set-screw orsimilar fastening device which renders it impossible to loosen such set- ;screw or other fastening device without first removing the shield or guard, and this latter can be done only by. the owner or other authorized person provided with a means for removing the same.

Briefly described, the invention may be said to con-- sist in the combination with a fastening devicehaving a. squared head or nut rorming a wrench-hold and one element of a locking means, of a guard in the nature 01 a casing adapted to completely incase such head or nut and provided with the other element of a lock, said casing being rotatable relatively'to said head or nut, so that the fasteningdevice cannot be unscrewed by merely rotating the guard.

Our invention will be readily understood when conber carrying the movable locking tongue and a por-' tion of the lock whereby said movable'locking tongue is secured in operative position.

Referring to the drawings, 5 may indicate an ordinary lantern bracket; such as is commonly secured to the dash, or other part of a vehicle, and 6 designates the vertical post constituting the upward extension of said bracket, over which fits the usual vertical sleeve' 7 \constituting the end member of the shank 8 of'the lantern'or other article supported by the bracket.

9 designates the threaded stem of a set-screw, which screws into a threaded hole in. one sideof the sleeve 7 and is adapted to impinge tightly against the post 6 to prevent accidental displacement of the sleeve 7, in a manner well understood. The head of the settion of a wrench .to tighten and loosen the set-screw, as usual,- and in rear oi the squared portion it is provided with an annular groove 11 that constitutes one element of the means for locking the shield or guard upon the head of the set-screw. I

12 designates a cup-shapedcasing having a round bore, the open end of Which casing is adapted to fit over the head of the set-screw, as clearly shown in Fig.

'l. The inner wall of the casing is provided on its lower side with an arc-shaped stationary locking tongue 13, that engages the groove 11 of the head. The upper portion of the casing has a longitudinal slot formed between parallel longitudinal ribs 12 thereon; and

pivoted in this slot substantially coincident .with the inner or open edge of the casing is a locking bar 14,

i which bar has formed integral therewith on its under side a short arc-shaped tongue 15-that also, when the bar is in closed position, enters the upper side of the groovev 11 of the head and cooperates with the fixedscrew has the usual squared portion 10 for the applicatongue 13 in locking the casing upon the head. To

' secure the bar 14 in closed position, it is provided at its free end with'a depending hook 16 that constitutes one element of a spring lock mechanism mounted in the closed end of the casing, which spring lock mechanism may be of any of the lmown forms or types controlled by a key inserted through the key-hole indicated at 17.

From the foregoing it will be apparent that when the bar 14 is located in its closed position, the locking tongues 13 and 15 are so engaged with the locking groove 11 of the head that the guard or casing cannot be removed from the head, although said casing can be freely rotated on the head in either direction without effecting any turning movement of the latter. Hence the'set-screw cannot be loosened by any amount of turning of the guard when the latter is locked on the head. To remove the guard, a key is inserted in the key-hole 17, and turned sufficiently to release the hook 16, whereupon the arm 14 springs upwardly, or

.may be raised, according to the character of the spring lock controlled by the key; and the raising of said arm retracts the locking tongue 15 from the groove 11 and enables the guard to be readily withdrawn.

From the foregoing it will be apparent that the device of our invention provides a safety device against tampering with the set-screw by unauthorized persons, in that, when applied, it prevents the application of a wrench or other loosening tool, and, being itself rotatable upon and relatively to the set-screw, prevents the possibility of loosening the latter through turning of, the guard. The device is cheaply made and quickly applied and removed; and requires no alteration .or special construction of the screw-head Q nut oth than to provide therein a simple a nularlocking groove. While We have shown thedevice-as applied to the head'oi asetscreW, it will, of course, be understood that it is equally applicable to the same advantage to the nut or head of a bolt, or any other locking member, of a guard incaslng said wrench-hold and.

provided with a movable key-controlled cooperating locking 7 member, said coiiperating locking members preventing removal but permitting rotation of said guard upon said fastening device, substantially as described.

2. In a. guard of the character described, the combination with a fastening devicehaving avwrench-hold and an annular locking groove, of a guard incasing said wrench-hold and provided with a removable key-controlled locking tongue adapted to engage said locking groove in a manner to prevent removal but permit rotation of said guard upon said fastening device, substantially as described.

3. In a guard of the character described, .the combination with a set-screw having-a squared head provided with an annular groove, of a guard incaslng said head, said guard having a key-controlled pivoted member carrying a locking tongue adapted to engage said annular groove in a mannerto prevent withdrawal but permit rotation of said guard upon said head, substantially as described.

4. In-a guard of the character described, the combina- 'tion with a set-screw having a squared head provided with an annular groove, of a guard incasing said head, said guard having a fixed inwardly projecting locking tongue engaging said groove and further having a key-controlled pivoted member carrying a locking tongue adaptedto engage said annulargroove at a point opposite said fixed locking tongue, whereby said guard may be locked rotatably upon said head, substantially as described.

KARL n. AHLBERG; JOSEPH AHLBERG.

Witnesses SAMUEL N. POND, FREDERICK C. Gooowm. 

